Fairfax County officials on Tuesday approved a landmark proposal to allow the transformation of Tysons Corner from a sprawling, auto-dependent office park into vibrant, walkable city.

The Board of Supervisors voted 8 to 2 after a six-hour public hearing on new building rules and a 20-year blueprint for Tysons, its most significant land-use decision in recent years. The proposal permits Tysons to become a city of office and residential towers with sidewalk cafes, boutiques and manicured courtyards. It also calls for energy-efficient buildings, affordable housing, park space and a new street grid to filter local traffic. A planned circulator bus system would ferry riders among future Metrorail stations, offices and shopping malls.

"Tysons is a downtown. While it may not be a municipality, it will be a community," Supervisor Catherine M. Hudgins (D-Hunter Mill), whose district includes the employment hub, said before the vote. "Tysons is not going to be an auto-oriented environment. It's going to be walkable for the people who live there and for the economy."

Decades of growth turned Tysons from a rural crossroads into the nation's 12th-largest business district, home to the corporate headquarters of companies including Capital One, Freddie Mac, Booz Allen Hamilton and Hilton Worldwide. But it also created a sprawling expanse of high-rise buildings and wide, congested roads, prompting county officials to revaluate the area's future.

The proposal, which was recommended by the Planning Commission last month, permits the densest development within a quarter-mile of four Silver Line Metro stations being built as part of the rail extension to Dulles International Airport. At least 75 percent of all development would be located within half a mile. The plan places no limit on residential projects in housing-starved Tysons but caps office development at 45 million square feet through 2030. About 27 million square feet of office space exists in Tysons, with plans for 6 million more approved, including a future expansion of Tysons Corner Center.

The biggest hurdles have yet to come. Excluding the rail system, officials have yet to identify a way to fund about $1.5 billion in road and transit improvements needed through 2030.

The public hearing was the culmination of five years of planning. The county was under pressure to adopt a final land-use plan because the four Metro stations are slated to open in 2013.

The three Republican members of the Board of Supervisors attempted to delay a final vote until mid-July in what Frey called an attempt to "digest" the four hours of testimony heard Tuesday night "for transparency's sake."

But the seven Democrats on the board said too much time -- more than five years -- had been spent debating the plan's merits from the level of density allowed near Metro stations to building heights.

"This has been an extraordinary process that has involved so many people through it. It's been the whole spectrum, from business to landowners to neighbors," said Supervisor Linda Q. Smyth (D-Providence), whose district includes portions of Tysons. "And everyone has had so much opportunity for input."

Public speakers included nearly 70 people, a mix of residents, developers and members of advocacy groups.